Safety cover plate for electrical receptacles



l Jan. 21, 1958 J. v. MEls'rRELL SAFETY COVER PLATE FOR ELECTRICALRECEPTACLES Filed March l22, 1954 Y lf-sewn WKK* INVENTOR.

Joy/v ME/sreeu. BWM@ www United States Patent SAFETY COVER PLATE FOR ELECTRICAL RECEPTACLES John v. Matan-eli, Manhattan Beach, caiif.

Application March 22, 1954, Serial No. 417,852

4 Claims. (Cl. 174-67) My invention relates generally to electrical receptacles or outlets, and more particularly toa cover plate which is adapted to close the contact sockets when they are not in use.

Since the electrical contacts of the conventional outlet are continuously energized they represent a source of danger for electrical shocks and short circuits. While the prongs of an electrical plug are designed to be safely inserted within the contact sockets, it is possible to cause a short circuit by the insertion of a wire or other metal object into the sockets Small children fail to appreciate this danger' and are often injured by such an accident.

Many attempts have been made to make the electrical receptacle more safe by the provision of closure mechanisms that close off the contact sockets when a plug is not engaged therein. A major difficulty with such prior devices is that they require the changing of all of the household electrical receptacles from the conventional type to the type embodying the closure mechanism. Some even require the use of a special electrical plug for operation. In addition to the expense involved in purchasing new receptacles, such a change requires a competent electrician to see that the new receptacles are properly connected in place, necessitates shutting off the power supply, and involves various other troubles. For these economic reasons alone, such safety receptacles have not gained widespread use.

In addition, many of the prior closure mechanisms are not easily operable, and in particular, make it difficult to insert the prongs of the plug in the socket when it is desired to use the receptacle. Still other devices are so complex in construction as to be easily damaged and otherwise impractical for extended usage.

A primary purpose of this invention is to provide protective means for the electrical receptacle which are embodied entirely within a cover plate that replaces the usual decorative cover plates. The use of cover plates to cover the unsightly portions of the receptacle and the surrounding portions of the outlet box and wall edges is universal practice in all modern electrical installations. Such cover plates are secured to the receptacle by one or two screws and are quite easy to remove and replace. More important, the cover plates are not connected to the electrical circuits in any manner, and the changing of them may be done by the most inexperienced person, without danger. It is also obvious that the changing of the cover plates alone is considerably less expensive than replacing all of the electrical receptacles.

An equally important object of the invention is to provide a safety cover plate having shutter means which are easily moved from a position closing the contact sockets to a position permitting the insertion of electrical prongs therein.

It is also an object of the invention to provide a cover plate having shutter means which are movable to a limitingposition in whichfexact and simple alignment of Patented Jan. 21, 1958` the electrical prongs for insertion inthe contact sockets is made possible.

A further object of the invention is to provide a cover plate of compact and simple design whereby to replace the conventional cover plates without noticeable change in appearance.

Still another object of the invention is to provide a safety cover plate having a minimum number of rugged and durable parts, and so designed as to protect the operating mechanism from damage.

These and other objects and advantages of the invention will become apparent from the following detailed description of a preferred form thereof, and from an inspection of the accompanying drawings, in which: A

Figure l is a perspective view showing the preferred form of safety cover plate installed in place;

Figure 2 is a vertical section taken along thev line 2-2 of Figure l; l

Figure 3 is a cross-section taken along the line 3 3 of Figure l, showing the shutters in closed position;

Figure 4 is a view similar to Figure 3 showing the shutters in open position; and

Fig. 5 is an exploded view showing the various elements of the device.

Referring now to the drawings and particularly Figure l thereof, the numeral 10 indicates generally a preferred form of the cover plate. As illustrated, plate 10 is designed for use with a dual electrical receptacle or outlet, but it may also be designed for use with a single outlet. Plate 1t) is of rectangular shape and is typically of the same dimensions as the conventional cover plate which it is designed to replace.

As is ybest seen in Figure 2, plate 10 is adapted to be secured to a conventional electrical receptacle 11 by a typical center mounting screw 12. Receptacle 11 is of rectangular block shape and is normally fixed in position by a rear mounting strap 13 having end portions fastenable to a rigid outlet box not shown. On the front of receptacle 11 are upper and lower socket faces 14 and 15 which are extended slightly forward from the body of the receptacle and are of generally circular shape. The faces 14 and 15 normally define a surface of contact to abut the end face of an electrical plug and are each provided with rearwardly open sockets 16 leading into the body of the receptacle. ln the usual two wire circuits, a pair of such sockets 16 are placed side by side and are of elongated vertically extending shape. Within the sockets 16 are electrical contacts 18 (Figures 3 and 4) adapted to be engaged by prongs 19 projecting from a standard electrical plug 20 that is secured to the end of anextension wire 21. Suitable conductors from the wiring circuit lead to receptacle 11 and are connected to the contacts 18. The receptacle 11 and the plug 20 are, of course, commonplace and form no part of my invention, being merely describedherein to illustrate the operation of my safety cover plate.

Returning to the cover plate 10, it will be seen to be formed of built up construction. Preferably, plate 10 is of plastic construction but other insulating materials may be used. Plate 1t) has a rear wall 25 which may best be seen in Figure 5. Vertically spaced `within the wa1l25 are a pair of upper and lower openings 26 and 27 which are shaped to receive the socket faces 14 and 15 therein. Surrounding each of the openings 26 and 27 is an enlarged forwardly open recess 29 which is lof shallow -depth and rectangular shape. Recesses 29 are separated by a central bar 30 and the latter may be apertured at 31 to receive securing screw 12.

In order to lighten wall 25 it may be provided with open portions 33 surrounding the openings 26 and 27. However, at one side of openings 26 and 27 a solid wall portion 34 is provided and therein aredelined shallow troughs 35, l

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Troughs 35`ext'end laterally towards the openings 26 and 27 butV are spaced therefrom so as to` have solid end surfaces. It should also be noted' that the depth of openings 2,6,and 27 rearwardly of the recesses 29 is substantially equal to the depth of socket faces 14 and 15. Thus the socket faces 14 and 1S lie flush with the rear wall surface of recesses29 when the cover plate is installed.

Mounted within each of the recesses 29 is a thin shutter 38' of rectangular shape and formed of non-conducting material. Shutters 38 are of the same height as recesses 29 but' are of reduced width so as to be laterally slidable therein. The thickness of'shutters 38 is just equal to the depth of recesses 29 so that the outer surfaces of the shutters are substantially flush with the front of wall 25.

lA front wall 39 is` secured to rear wall 25 around the outer edges thereof so as to hold shutters 38 within recesses 29. Preferably, corner lugs 40 project rearwardly from front wall 39 and' are adapted to engage within apertures 41 in rear wall 25 to secure the walls tightly together. The rim of wall 39 may also be bonded to wall 25 by a suitable adhesive, if desired. Within the front of wall 39 is an enlarged opening 42 of a shape, as is best seen in Figure l, to expose substantially all of the central portion of both the shutters 38 as well as the central bar 30. Opening 42 permits plugs 20 to be placed directly against shutters 38 so as to engage within the receptacle 11.

Shutters 38 are each provided with spaced vertical slots 45 therein which are of a size and location to receive the electrical prongs 19 therethrough. As is best seen in Figure 3, when shutters 38 are moved to the right hand end of recesses 29, the slots 45 do not align with either of the contact sockets 16. Therefore, it is not possible to pass a wirev or other object through slots 45 to make electrical connection with the internal socket contacts 18. This prevents accidental electrical shocks or short circuits, and is a very advantageous safeguard for small children.

In order to hold shutters 38 normally in the position shown in Figure 3, I provide spring means 46 which urge the 4shutters to the right. Spring means 46 take the form of small coil springs which are mounted Within troughs 35. The diametral width of springs 46 is such that they project forwardly from the shallow troughs 35 into the recesses 29 and are thus adapted to engage the edge of shutters 38.

With shutters 38 in the position of Figure 3, the insertion of electrical prongs 19 into slots 45 is limited by engagement with the front of receptacle 11. When it is desired to connect a plug 20 to receptacle 11, the prongs 19 are fitted into sl-'ots 45 and are then used as keys to move shutter 38 to the left against the urging of spring 46. l

When spring 46 is fully compressed, the shutter 38 has moved into the position shown in Figure 4. Prongs 19, slots 45, and sockets 16 are then all in alignment, and plug 20 may be pushed inwardly so that prongs 19 engage against the electrical contacts 18. Once prongs 19 have entered within sockets 16, the shutter 38 is prevented from moving to the right under the urging of springs 46. It should particularly be noted that the limiting position of shutter 38 as shown in Figure 4 is such as to cause exact alignment between slots 45 and sockets 16. Thus, there is no difficulty in inserting prongs 19, since shutter 38 is merely pushed as far as it will go to the left, and in this position the prongs 19 are easily pushed into sockets 16.

From the foregoing it can be seen that I have provided a safety cover plate which can be used with any conventional receptacle and does not require electrical work for installation. Changes of design and construction may be made without departing from the scope of the invention, and I do not wish to be restricted to the foregoing details except as defined in the appended claims.

I claim:

1. A safety cover plate for installation on an electrical receptacle of the plug-in type, which comprises: a hat rear wall having an opening adapted to receive 'the socket face-of said receptacle and an enlarged forwardly open recess of rectangular shape, said wall having a short laterally eatending trough therein at the side of said opening; a shutter mounted for lateral sliding movement in said. recess directly in front of the plane of said receptacle socket faces, and formed with spaced slots therein for receiving therethrough the prongs of an electrical plug; a forward wall secured to said rear wall and conlining said shutter to said recess, said forward wall having an opening therein exposing the face of said shutter surrounding said slots and of a size larger than the face of a standard electrical plug whereby sai-d plug may seat directly against said shutter; and spring means confined within said trough andy projecting forwardly into said recess to engage with said shutter for urging said shutter to a position wherein said slots are out of alignment with the contact sockets of said receptacle, and yieldable so that said shutter may be moved to align said slots with said contact sockets.

2. A safety cover plate for installation on an electrical receptacle of the plug-in typc,which comprises: a flat rear wall having an opening adapted to receive the socket face of said receptacle and an enlarged forwardly open recess of rectangular shape, said wall having a short laterally extending trough therein at the side of said opening; a shutter mounted for lateral sliding movement in said recess directly in front of the plane of said receptacle socket faces, and formed with spaced Slots therein for receiving therethrough the prongs of an electrical plug, said shutter being movable from a iirst limiting position wherein said slots are all out of alignment with the contact sockets of said receptacle to a second limiting position wherein said slots are aligned with said contact sockets; a forward wall secured to said rear Wall and confining said shutter to said recess, said forward wall having an opening therein exposing the face of said shutter surrounding said slots and of a size larger than the face of a standard electrical plug whereby said plug may seat directly against said shutter; and spring means conlined within said trough and projecting forwardly into saidV recess to engage with said shutter for urging said shutter to said first limiting position and yieldable so that said shutter may be moved to said second limiting position.

3. A safety cover plate for installation on an electrical receptacle of the plug-in type, which comprises: a hat rear Wall formed of insulating material and having a generally circular opening adapted to receive the socket face of said receptacle and an enlarged forwardly open recess of rectangular shape and shallow depth, said wall having a short laterally extending trough therein spaced from the side of said opening; a thin shutter formed of insulating material and mounted for lateral sliding movement in said recess directly in front of the plane of said receptacle socket faces, said shutter having spaced slots for receiving therethrough the prongs of an electrical plug and being movable from a first limiting position wherein said slots are all out of alignment with the contact sockets of said receptacle to a second limiting position wherein said slots are aligned with said contact sockets; a forward wall formed of insulating material and abutting said rear wall around said .recess and secured thereto for confining said shutter to said recess, said forward wall having an opening thereinA exposing the face of said shutter around said slots and of a size larger than the face of a standard electrical plug whereby saidplug may seat directly against said shutter; and a coil spring mounted Within said trough and partially `projecting forwardly into said recess to engage with an edge of said shutter for urging said shutter to said first limiting position and yieldable so that said shutter may be moved to said second limiting position.4 y

4. A safety cover plate for installation on a dual electrical receptacle of the plug-in type, which comprises: a iat rear wall formed of insulating material and having a pair of vertically spaced openings therein adapted to receive the socket faces of saidreceptacle therein and an enlarged forwardly open recess of rectangular shape and shallow depth around each opening, said wall having a short laterally extending trough therein spaced from the side of each of said openings; a thin shutter formed of insulating material and mounted for lateral sliding movement in each of said recesses directly in front of the plane of said receptacle socket faces, said shutter having spaced slots receiving therethrough the prongs of an electrical plug and being movable from a first limiting position wherein said slots are all out of alignment with the contact sockets of said receptacle to a second limiting position wherein said slots are aligned with said contact sockets; a forward wall formed of insulating material, abutting said rear wal1 around the edge thereof and secured thereto for confining said shutters to said recesses, 15 2,641,627

said forward wall having a central opening therein exposing the faces of said shutters around said slots and of a size larger than the face of a standard electrical plug whereby said plug may seat directly against said shutter; and a coil spring mounted within each of said troughs and partially projecting forwardly into said recesses to engage with an edge of said shutters for urging said shutters to said first limiting position and yieldable so that said shutters may be moved to said second limiting 10 position.

References Cited in the tile of this patent UNITED STATES PATENTS Huber Aug. 2, 1949 Lewis June 9, 1953 

